i have seen the documents in
http://www.haskell.org/haskellwiki/Generalised_algebraic_datatype
but i can not run the following code on ghci
ex:
data Term x where
K :: Term (a - b - a)
S :: Term ((a - b - c) - (a - b) - a - c)
Const :: a - Term a
(:@) :: Term (a - b) - (Term a) -
On Nov 27, 2007 12:57 PM, Yu-Teh Shen [EMAIL PROTECTED] wrote:
i have seen the documents in
http://www.haskell.org/haskellwiki/Generalised_algebraic_datatype
but i can not run the following code on ghci
ex:
data Term x where
K :: Term (a - b - a)
S :: Term ((a - b - c) - (a - b)
Thanks.
So GADT provide us to generic type to include all types, is it right?
ex:
data Parser tok a where
Zero :: Parser tok ()
One :: Parser tok ()
Check :: (tok - Bool) - Parser tok tok
Satisfy :: ([tok] - Bool) - Parser tok [tok]
Push :: tok - Parser tok a - Parser tok a
Luke Palmer wrote:
You can also put the line
{-# OPTIONS_GHC -fglasgow-exts #-}
At the top, to turn on glasgow extensions whenever GHC compiles this file.
I was under the impression that it's better to use the LANGUAGE pragma
rather than the catch-all Glasgow-exts option. However, I
On Tue, Nov 27, 2007 at 07:11:27PM +, Andrew Coppin wrote:
I was under the impression that it's better to use the LANGUAGE pragma
rather than the catch-all Glasgow-exts option. However, I can't actually
find a language option for GADTs... somebody care to clarify?
In GHC 6.8.1 it's
On Tue, 2007-11-27 at 19:11 +, Andrew Coppin wrote:
Luke Palmer wrote:
You can also put the line
{-# OPTIONS_GHC -fglasgow-exts #-}
At the top, to turn on glasgow extensions whenever GHC compiles this file.
I was under the impression that it's better to use the LANGUAGE
